1. Field of Invention
The present invention relates to a high-efficiency magnetic reactor-type ballast, particularly of a kind operable to power two fluorescent lamps from a 277Volt/60Hz power line.
2. Prior Art
For reasons of cost-effectivity, electric power distribution in new commercial buildings is almost exclusively accomplished by way of a 277Volt/60Hz distribution voltage. At that voltage, ballasting of two 48" T-12 fluorescent lamps--which represent the most commonly used type of lamp combination/arrangement--could have been done by way of a simple reactor means; which would have led to a very efficient and cost-effective ballast. However, because of U.L. requirements relative to shock hazard safety, it is in reality not permissible to do the ballasting that way. As a consequence, a much more elaborate transformer-based ballast has to be used for powering two 48" T-12 fluorescent lamps from 277Volt/60Hz power line voltage.
Due to the substantial use of transformer action, a significant cost penalty and efficiency reduction result.